Monarch Migration Update: October 6, 1998
Today's Report Includes:
Monarchs Expected to Pour into Texas This Week
If you live in Texas, watch for monarchs to arrive as the winds to shift to the north. A big storm,
showing the classic comma shape in its cloud pattern, is spiraling over the Northern Plains and Upper Midwest.
Observers there predict that this storm system will deliver the first strong cold front --and the monarchs--to
Texas:
"No sightings to report yet, but a cool front is moving in," says Shirley Dean of Abilene State Park
in Tuscola. "Our first 'cool' front is expected Tuesday ... maybe a Texas 'fall' by next weekend and then
the Monarchs in full migration," predicts Harlen E. and Altus Aschen of Port Lavaca, TX.
"A front is finally approaching. Right now, fierce winds with gusts of 40 mph are blowing out of the south,
but it should shift to the north any hour - very exciting," reported Bill Calvert of Texas Monarch Watch on
Monday morning. "Migrating monarchs have been reported in numbers as far south as southern Kansas and central
Oklahoma but they have not yet arrived in Texas--they are late. We usually see them in north Texas by late September.
This may be due to the lack of strong fronts forming this year."
Over the weekend, monarchs in western Kansas were among those apparently poised to fly south as soon as the
winds shift:
10/04/98 Nashville, KS (37.42N, -98.40 W)
"This afternoon, shortly after a hail storm our family saw 200-300 Monarch Butterflies. We were lucky to
see such a beautiful sight! They were flying around in our yard and landed on the north side of a elm tree and
several landed on the north side of our cedar trees. There was a strong south wind." (yabuddy@havilandtelco.com)
10/02/98 Sublette, KS (37.56N, -100.79W)
"Thousands+ monarchs entered into our area (S.W. Kansas) 2 days ago (October 2). Today (01/05/98) strong winds
are out of the south, keeping them in our trees & weeds for protection. This is by far the largest amount of
Monarchs that has moved through our area in many years! (bewise@pld.com)
Watch for an update from Texas next week. We hope to report that the migration has finally arrived there in
full force. Here are other sightings reported this week:
Why No Summer Monarchs in Texas?
Discussion of Challenge Question #3
The monarchs' arrival in Texas is quite clear each year, since few are seen there since the previous spring. We
asked, "Why aren't monarchs usually found in Texas from June until September?"
Two 5th graders at Becky-David Elementary in St. Charles, MO shared their thoughts:
"Dear Journey North, I think that the climate in Texas is too hot and dry for the butterflies to live,"
said Kailey. "I think that the vegetation in Texas is wrong for the Monarchs and that is why they do not stay
there," suspected Rachel.
Texas Monarch biologist Dr. Bill Calvert gives his views of the monarch's "seasons" in the his state:
"Here in Austin, TX (30 N), monarchs disappear sometime in June. (Not all of them, of course, but the bulk
of them.) Then they reappear in early September, or perhaps even late August.
"There are 3 important milkweed species which monarch larvae feed on here. What happens here in Texas to the
larval food plants depends on the species. Two milkweed species (A. viridis and A. asperula) have a strong growing
and maturing spurt in the spring--at the same time that monarchs are present in the spring. Both species seem
to die back in June and July, essentially disappearing during the summer. A 3rd milkweed species (A. Oenotheroides)
is different. It grows in the spring and some of it does flower, but at this latitude most of the flowering occurs
in the fall. It also seems to senesce or aestivate during the hot summer. Thus, when the milkweeds reappear, so
do the monarchs.
"The reasons behind this are controversial. Zaluki and Malcolm (monarch biologists) think that monarchs can't
survive the heat, e.g. it is the heat per se that kills them. But there are so many reports of monarchs present
in high heat that it doesn't seem possible that heat kills them. It may be a simple matter of food plant senescence
during the hot summer months. ("Senescence" is when plants age or die back. )
"As I mentioned, monarchs reappear here in early September or even late August. It is still extremely hot
in Texas then, and yet there is a flourishing monarch population. This is the principal reason that I think the
system is host plant - not temperature-- driven. (Allowing for the possibility that heat plays a strong role in
host plant cycles.)"
Special Butterflies Heading for Mexico
Monarchs have recently joined the migration, after being raised and released by:
David Lipscomb Elementary, Nashville, TN
Cleardale Public School, London, ON
Highland Catholic School, St. Paul, MN
St. Mary Academy, Dover, NH
McKnight Elementary School, Pittsburgh, PA
Captain Isaac Paine School, Foster, RI
Marvin Heights Public School, Mississauga, ON
Let us know when your monarchs are on their way!
Coming Next Week: Discussion of Challenge Question #4
If you haven't done so yet, read last week's update and
send your answer to this question:
Challenge Question #4
"Do you think the data collected so far at Cape May show there a fewer monarchs this fall than usual? Why
or why not?" Include specific examples from the data to support your answer.
- Address an e-mail message to: jn-challenge-monarch@learner.org
- In the Subject Line of your message write: Challenge Question # 4
- In the body of the message, answer the question above.
The Next Monarch Migration Update Will be Posted on October 13, 1998.
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